Feeding device for roller mills for cereal products



Sept. 14, 1954 BALL 2,689,063

FEEDING DEVICE FOR ROLLER MILLS FOR CEREAL PRODUCTS Filed Oct. 12. 1950 s Sheets-Sheet 1 Sept. 14, 1954 J. 5. BALL 2,689,063 FEEDING DEVICE FOR ROLLER MILLS FOR CEREAL PRODUCTS Filed Oct. 12 1950 3 Sheets-Sheet 2 J. 5. BALL Sept. 14, 1954 FEEDING DEVICE FOR ROLLER MILLS FOR CEREAL PRODUCTS 3 Sheets-Sheet 3 Filed Oct. 12 1950 Patented Sept. 14, 1954 UNITED STATES PATENT OFFICE FEEDING DEVICE FOR ROLLER MILLS FOR CEREAL PRODUCTS Claims priority, application Great Britain November 3, 1949 2 Claims.

In roller mills for cereal products the feeding device usually consists of a feed roller or pair of rollers parallel to and extending the full length of the grinding rolls. Above the feed roller is placed a hopper, also extending the full length of the rolls, into which the stock to be ground is fed in such a way that it spreads to the full length of the hopper. At the bottom of the front plate of the hopper is a gap closed by a gate which provides a variable narrow slit above the top of the feed roller. The feed roller is provided with longitudinal grooves or flutes which, as the roller rotates, draw the stock from the hopper through the gap formed with the gate. The distance of the gate from the roller is automatically controlled by the height of the stock in the hopper, so that if the feed increases and the height of the stock is raised, the gate opens to allow more stock to be drawn out, whilst if the feed is reduced, the gate closes and reduces the flow of stock. In this way, the height of the stock in the hopper is kept approximately at a constant level and a uniform curtain of stock is maintained along the full length of the roller mill.

This arrangement is quite satisfactory for free running granular stocks like semolinas, but as stocks containing large numbers of flakey particles will not flow easily through a narrow gap, the opening of the gate has to be considerably increased before an increase in the flow of such stocks is obtained, and it is not possible to obtain a regular variation in the delivery of stock from the roller. Consequently the gate is sluggish and tends to hunt with the result that the feed to the grinding rolls is irregular and there is a tendency for the stock to back up and choke in the feed spout. Varying the speed of the feed roller in accordance with the variation of the feed provides a means of regulating the feed which does not rely on a change in the width of the gap and attempts have been made to produce a mechanically operated device of this sort. Such devices have, however, been unsuccessful owing to the power required to operate the speed-varying mechanism satisfactorily being greater than could be provided by the variations in the flow of stock.

The object of the present invention is to provide improved means for controlling the speed of the feed roll or rolls which respond rapidly to any variation in the feed to the machine and which require a minimum of power for their operation.

The invention consists in a roller mill for cereal products in which the feed rollers are driven hydraulically and in which the supply of hydraulic fluid to the hydraulic driving motor is under the control of the balance plate or like means in the feed hopper of the mill so that the position of such plate or the like which is determined by the head of stock in the hopper controls the speed of the motor and of the feed rollers.

The invention further comprises a roller mill in which a hydraulic pump and a hydraulic motor are located in a common casing which forms a reservoir for the operating fluid and in which a release valve in such casing on the fluid connection between pump and motor is controlled from the balance plate or the like.

The invention further comprises a roller mill in which a hydraulic pump and a hydraulic motor are located in a common casing which forms a reservoir for the operating fluid and in which a valve or cook in the fluid connection between pump and motor regulates the flow between the latter or cuts off such flow, there being safety valves on the pump and in the valve or cock.

Referring to the accompanying explanatory drawings:

Figure 1 is a diagrammatic view showing a typical feed arrangement for a roller mill, to which my invention is applied.

Figures 2 and 3 show two convenient arrangements in accordance with this invention for controlling the speed of the feed rollers of the roller mill in accordance with the head of stock in the feed hopper supplying the rollers.

The left hand portion of a duplex machine will be described with reference to Figure 1.

a are the grinding rolls, 1) the feed rolls. 0 the pivoting feed gate which has its position controlled by the'balance plate d, upon which the weight of stock in the feed hopper e rests. The balance plate d which is counter-balanced to move upwards in the hopper to its full line position turns the lever f to which it is attached and which has its fulcrum at g. A roller it has its axle adjustably secured in a slot 2' in the lever 1. Such roller bears against an army secured to the feed gate 0 which pivots about It. The lever f is also connected by the link m to an arm n rigid with a slotted arm 0, see Figure 2, which adjusts a weight 10 along an arm q pivoted at 1', which serves to load a ball valve 3 through the rod t. u is a hydraulic pump driven by the pulley v, the delivery from the pump driving the hydraulic motor w driving the shaft :0 of the feed roller b. The valve s forms a release valve for the pressure fluid passing between the pump and motor and so acts to control the speed of such motor in accordance with the position of the balance plate 11 through the means before described.

In the modification shown in Figure 3, the arm n acts through the connecting rod 2 and arm 3 to control the position of a cook or valve 4 which can regulate the rate of flow of hydraulic fluid from the pump a to the motor w or can out 01f such flow entirely. A safety valve 5 is provided on the pump and a safety valve 6 on the valve 4.

The hydraulic pump and motor may be of any convenient type and may be driven or drive directly or indirectly. They are preferably located in a single casing as shown which forms a reservoir for the operating fluid.

My improved apparatus provides a positively drive feeding device which is highly sensitive and responds rapidly to any variation in the feed to the machine.

What I claim is: l

1. A roller mill for cereal products comprising, in combination, a revolving feed roll, a pivotally mounted feed gate between which and the feed roll the stock passes, a hopper supplying stock to said feed roll, a pivotally mounted and counterbalanced plate projecting into said hopper and pressed upon by the stock passing down the hopper, means operatively connecting said plate 3 to said feed gate so that the weight of stock pressing on the plate controls the gap between the feed gate and feed roll, a hydraulic motor driving the feed roll, a hydraulic pump supplying pressure fluid to said motor, a pressure release valve on the fluid connection between the hydraulic pump and motor, a lever loading said valve a weight movable along said lever to vary the loading of said valve, a control lever moving said weight along said lever, and an operative connection between said control lever and said pivotally mounted and counterbalanced plate.

2. A roller mill for cereal products comprising,

'in combination, a revolving feed roll, a pivotally sure release valve on the delivery side of the hydraulic pump, a valve between the pump and motor for cutting off the fluid supply to the motor, a lever operating said last mentioned valve and an operative connection between said lever and said pivotally mounted and counterbalanced plate.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,120,584 Brown Dec. 21, 1937 FOREIGN PATENTS Number Country Date 755,079 France Nov. 18, 1933 

